Question

multiple choice question
at some point in their life cycle, all chordates have a postanal tail, ____, hollow nerve cord, and ____.
lungs; notochord
endoskeleton made of bone or cartilage; lungs
pharyngeal slits or pouches; endoskeleton made of bone or cartilage
notochord; pharyngeal slits or pouches

Explanation:

Chordates have four key characteristics at some stage of their life cycle: a post - anal tail, a notochord (a flexible rod - like structure), a hollow nerve cord, and pharyngeal slits or pouches. Lungs are not a universal chordate feature (e.g., fish have gills). An endoskeleton made of bone or cartilage is a characteristic of vertebrates (a sub - group of chordates), not all chordates.

Answer:

notochord; pharyngeal slits or pouches